Overview of Options
The morphology of kelp plants makes them relatively easy to study in
the field because the individual plants are large and easy to count, and because the basal
meristem permits the growth of plants to be measured in situ by following the
movement of punched holes away from the base of the blade. Consequently, kelps have
probably received more scientific attention than any other group of seaweeds, and the
habitats dominated by them have also been fairly well. Nevertheless, there are significant
gaps in our knowledge of the ecology of even the commonest kelp species, and much larger
gaps in the information available about the animal and plant species that are associated
with kelps in kelp forests.
- It is still not possible to define which of these associated species are really
diagnostic of, or endemic to, kelp ecosystems, as opposed to those which are favoured by
the physical, chemical or biological conditions that a kelp forest creates.
Clearly, the kelp species, themselves, are diagnostic of kelp biotopes,
and they would certainly be selected for inclusion in an ACE survey (Abundance
scale, Check list and Exact location; Hiscock, 1998a) as important or
conspicuous species, as keystone species, as indicator species
and, possibly, also as sensitive species, in view of their susceptibility to
human impact. However, in spite of the wealth of information about the ecology of kelp
species, it is not easy to select one or two attributes of kelp plants (e.g. density of
plants per unit area, stipe dimensions, blade dimensions, growth rate of blades) that
could be easily measured in the field and used as an indicator of the health of a kelp
forest or ecosystem.
It is also possible that some of the floral and faunal species
associated with the blades, the stipes or the holdfasts of the plants, or the substratum
or water within the kelp forest, could provide an indication of impending changes in the
forest before the large, perennial kelp plants, themselves, begin to react.
However, our knowledge of these associated species has barely got beyond the descriptive
phase, and we are not yet in a position to say which species should be targeted as
potentially sensitive indicators of change.
- The identification of the keystone species in kelp biotopes should receive the highest
Much of the basic research on kelp biotopes that has been undertaken so
far, particularly in Europe, has not been directed to the management of these biotopes in
their entirety although, as discussed in Chapter V, some recent work has sought to examine
the effects of harvesting the kelp on the subsequent recovery of the kelp and its
In view of the global paucity of management-directed studies on kelp
beds, it is difficult to answer even the simplest of management questions. Monitoring
options suggested here can, therefore, be based on little more than informed speculation.
Firm recommendations could be offered only when the agencies responsible for managing kelp
biotopes had reached decisions, based on biological and environmental evidence or legal
obligations imposed by statutory bodies, about precisely what is to be
monitored and why it should be monitored.
Given adequate background and species specific information, scientists
will be able to develop optimal methods for the provision of reliable, reproducible,
accurate and relevant data to contribute to the management of the biotope. Conservation
and management agencies should make full use of CASE (or CAST in Northern Ireland)
research studentships as a cost-effective way of tackling specific management issues in
co-operation with marine biologists based in universities.
- The precautionary principle should be adopted until such time as dependable, scientific
methods for monitoring and surveilling all necessary aspects of the ecology of kelp
biotopes have been developed.